The prior art of cylinder locks and their operation is based on using a key whose various features serve to displace a number of pins, arranged as pin assemblies, to predefined positions, thereby allowing the rotation of the cylinder.
Cylinder locks are vulnerable to many methods of unauthorized manipulation, prominent among them the Bumpkey and Blowgun methods. These methods employ the well-known physical phenomenon of impact and momentum.
A tool for lock manipulation known as a Blowgun, is comprised of a narrow, strong metallic portion that is inserted into the lock keyway instead of a key, and a gun-like portion which imparts and transmits an impact-driven blow along the length of the metallic portion via the tumbler pins to the driver pins. In conjunction with the Blowgun, a tension rod is used to apply rotational force to the cylinder plug. When the impact-driven blow is transmitted to the driver pins and they are knocked out of position, clearing the shear line, the plug rotates slightly, due to the rotational force exerted by the tension bar, and thereby prevents the pins from returning to their locking position. The cylinder plug may now be freely rotated and the lock opened.
Using a Blowgun requires a great deal of expertise in order to discover the exact impact-driven blow intensity required. However, a simpler burglary tool, called the Bumpkey has been developed. Instead of using the narrow, metallic portion of the Blowgun, a key blank is used. The key blank depressions are all as deep as possible. In this method, a small hammer is used to impact the Bumpkey. Less expertise is required in order to discover the exact impact-driven blow intensity required. This new development compromises lock security and poses a grave danger to the public and a challenge to the cylinder lock industry,
Therefore, it would be desirable to provide a method and assembly for preventing unauthorized manipulation of common cylinder locks, as employed by burglars using methods based on the physical phenomenon of impact and momentum, such as the Bumpkey or Blowgun methods.